1. Field of the Invention
The present invention relates to a technique for controlling an event occurring probability, for example, an encountering probability that a character, moving on a map, encounters an enemy character in a video game.
2. Description of the Related Art
Of video games, there are RPGs (Role Playing Games) in which a player can make a game progress while he/she controls the game so as a character (hereinafter referred to as player character) to improve in accordance with a player operation. In general, the player character encounters in a constant probability another character (hereinafter referred to as enemy character), showing hostility toward the player character, while the player character moves on a map in RPGs. The player controls the game so that the player character battles the enemy character and the player character gains a predetermined experience level as a result of winning battle with enemy characters. The player character sequentially improves while increasing its power every time the experience value reaches a predetermined value.
In conventional RPGs, a constant probability that the player character encounters the enemy characters has been set, regardless of whether the enemy characters whom the player character encounters retain a high experience value or a low experience value. Generally speaking, whether enemy characters retain a high experience value or a low experience value depends on the power of the enemy characters, that is, their experience value is in proportion to their power. When the player character encounters an enemy character having a relatively low value, the player has to go through a troublesome battle against the enemy character, whereby the player character does not gain significantly due to the low experience value of the enemy character. Thus, the smooth progress of the game has been obstructed.
In some recently-developed RPGs, the probability that the player character encounters the enemy characters varies when the player character is equipped with a particular item. However, in equipping the player character such a particular item, the probability that the player character encounters the enemy characters can vary uniformly, regardless of the level of the player character. Due to this, in equipping the player character with such an item, an increase in the probability that the player character has to have an ineffective battle with the enemy characters for the sake of raising the power of the player character, or a decrease in the probability that the player character has an efficient battle against the enemy characters for the sake of raising the power of the player character occurs as a problematic matter.
It is an object of the present invention to provide a video game which can make a game progress smoothly by controlling a probability that an event, such as a battle against an enemy character etc., occurs.
According to the first aspect of the present invention, there is provided a video game apparatus comprising: event occurring area storage means for storing a position of an event occurring area on a map where a predetermined event is to occur and which is set on the map functioning as a movement area where a character moves in accordance with an externally transmitted input; area determination means for determining whether the character has reached the event occurring area stored in the event occurring area storage means; and event occurrence means for causing an event, set in the event occurring area, to occur in accordance with a probability corresponding to number of times in which an event has occurred in the event occurring area and/or number of times in which the occurring event has been completed, when the area determination means determines that the character has reached the event occurring area.
The event occurrence means may decrease the probability that the event will occur, in accordance with an increase in the number of times in which the event has occurred in the event occurring area or the number of times in which the occurring event has been completed.
The event occurrence means may cause the event, set in the event occurring area, to occur, when the number of times in which the event has occurred in the event occurring area or the number times in which the occurring event has been completed is a predetermined value.
In the above-described video game apparatus, an event occurring probability set for the event occurring area is controlled in accordance with the number of times in which the event has occurred or the number of times in which the occurring event has been completed, when the character has reached the event occurring area on the map. Particularly, in such a case where the event occurrence means decreases the probability that the event occurs if the number of times in which the event has occurred or the number of times in which the occurring event has been completed in the event occurring area increases, the player does not have to repeatedly go through troublesome battles against the enemy characters so that the game can progress smoothly.
When the number of times in which the event has occurred or the number of times at the occurring event has been completed in the event occurring area is a predetermined number, an event set for the event occurring area occurs. In such a case, if the predetermined value is, for example, 0, an event necessary for the progress of the game occurs at least once. Thus, the progress of game should be exciting enough.
The above-described video game apparatus may further comprise: setting value storage means for storing predetermined setting values in a manner corresponding to respective event occurring areas stored in the event occurring area storage means; and probability storage means for storing event occurring probabilities corresponding to the setting values stored in the setting value storage means. In this case, the event occurrence means may comprise: event occurrence determination means for determining whether to cause the event to occur in the event occurring area where the character has reached, in accordance with the occurring probability stored in the probability storage means and the setting value stored in the setting value storage means; event attaining means for attaining the event occurrence when the event occurrence determination means determines to cause the event to occur; and setting value updating means for updating the setting value of the event occurring area which is stored in the setting value storage means, when the event attaining means attains the event occurrence or the occurring event has been completed.
In such a case, the setting value storage means may store a single setting value corresponding to a plurality of event occurring areas.
The above-described video game apparatus may further comprise counting means for counting the number of times in which the event has occurred according to the event occurrence means or the number of times in which the event is completed, in the event occurring area. In such a case, the event occurrence means may comprise: means for performing a predetermined calculation on the basis of the number of times, counted by the counting means, in which the event has occurred in the event occurring area or the number of times in which the event has been completed, and for calculating a probability that the event is to occur in the event occurring area; and means for causing an event to occur in accordance with the probability which is calculated by the calculation means.
The above-described video game apparatus may further comprise: prior event information storage means for storing, in a manner corresponding to the event occurring area prior event information representing whether there is another event which is to be completed prior to the event occurrence in the event occurring area. In such a case, the event occurrence means may cause the event to occur in accordance with the prior event information corresponding to the event occurring area where the player character has reached.
It should be noted that the event in the above-described video game apparatus may be a battle held between the character and the enemy characters, for example.
The battle held between the character and the enemy characters may take place on the map functioning as the movement area where the player character moves. The event occurrence means may comprise operation mode changing means for changing the operation mode of the player character from a moving operation to a battling operation, when causing the event to occur.
According to the second aspect of the present invention, there is provided a video game apparatus comprising an input device, a storage device and a processing device, wherein the input device performs inputting to move a character on a map; the storage device stores a position of an event occurring area which is set on the map and where a predetermined event is to occur, and stores a program comprising: a character movement step of causing said character to move on the map in accordance with an input from the input device; a determination step of determining whether the character has reached the stored event occurring area; and an event occurrence step of causing the event, set in the event occurring area, to occur in accordance with a probability corresponding to the number of times in which the event has occurred in the event occurring area or number of times in which the occurring event has been completed, when it is determined that the character has reached the event occurring area: the processing device executes the program stored in the storage device; and the display device displays an image corresponding to a movement of the character on the map where the character moves when the processing device executes the character movement step of the program stored in the storage device, and an image corresponding to the event which occurs when the processing device executes the event occurrence step of the program.
The event occurrence step of the program decreases the number of times in which the event has occurred, in accordance with an increase in the number of times in which the event has occurred in the event occurring area which the character has reached or the number of times in which the occurring event has been completed.
The event occurrence step of the program may cause the event set in the event occurring area to occur, when the number of times in which the event has occurred in the event occurring area or the number of times in which the occurring event has been completed is a predetermined value.
In the above-described video game apparatus, the probability that the event set in the event occurring area occurs is controlled in accordance with the number of times in which the event has occurred or with the number of times in which the occurring event has been completed, when the player character has reached the event occurring area on the map. Particularly, in the event occurrence step, the probability that the event occurs decreases, if the number of times in which the event has occurred in the event occurring area or the number of times in which the occurring event has been completed increases. In such a case, the player does not have to go through continuously repeated troublesome battles against the enemy characters, so that the game progresses smoothly.
In the event occurrence step, when the number of times in which the event has occurred in the event occurring area or the number of times in which the occurring event has been completed is a predetermined value, the event set for the event occurring area occurs, under which condition an event necessary for the progress of the game occurs at least once. Thus, the progress of the game will be entertaining and exciting.
In the above-described video game apparatus, the event which occurs by executing the event step of the program may take place on the map where the player character moves. In such a case, the display device may process and displays a display image, at a transition from the movement of the player character on the map in the character movement step of the program to the occurrence of the event in the event occurrence step of the program.
Accordingly, the player can be easily informed that there is a transition from the general processing of moving the character on the map to the processing of executing the event.
The event in the above-described video game apparatus may be a battle held between the character and an enemy characters, for example.
The battle held between the character and the enemy characters may take place on the map functioning as a movement area where the player character can move. The event occurrence step of the program may include a step of changing the operation mode of the player character from moving to battling, when causing the event to occur.
In order to achieve the above-described object, according to the third aspect of the present invention, there is provided a method of controlling an event occurring probability comprising: a character movement step of causing a player character on a map to move in accordance with an externally transmitted input; a determination step of determining whether the character has reached an event occurring area which is pre-set on the map and where a predetermined event is to occur; and an event occurrence step of causing the event, set in the event occurring area, to occur in accordance with a probability corresponding to the number of times in which the event has occurred in the event occurring area or the number of times in which the occurring event has been completed, when it is determined that the character has reached the event occurring area.
The event occurrence step may decrease the number of times in which the event has occurred, when the number of times in which the event has occurred in the event occurring area where the character has reached or the number of times in which the occurring event has been completed has increased.
The event in the method of controlling the event occurring probability may, for example, be a battle held between the character and enemy characters.
When the method of controlling the event occurring probability, having the above steps is executed on a machine exclusively for games or a general-purpose computer, functions and effects similarly resulted from the above-described video game apparatus can be obtained thereon.
The above-described video game apparatus can be realized by storing on a storage medium a program for executing the respective steps which the method of controlling the event occurring probability comprises, reading the program into a computer from the storage medium and executing the same. By employing the form of the storage medium which stores the program, development, sales and distribution of the program can be produced as software media, independently separated from being as part of a device. By installing the program in the hardware of the general-purpose computer device, the above-described video game apparatus can likewise be realized.
The program or data for realizing the steps which the method of controlling the event occurring probability comprises may be embodied in a carrier wave, so that the program or data can be easily distributed and sold through some network.
Other advantages and meritorious features of the present invention will become more fully understood from the preferred embodiment, the claims, the drawings, and the brief description of which follows.